The present invention relates to panels for use in construction, and more particularly to composite panels for use in the construction of a house, other building or other structure.
Poured concrete and concrete blocks are used extremely widely in construction, for example as materials for the foundations and/or walls of houses, other buildings and other types of structures. Where concrete is used, it traditionally is poured at the building site, into forms built of wood or plywood on site, and removed after the concrete has set. This approach is labor-intensive, and the pouring can be done only when proper weather conditions exist. Accordingly, efforts have been made to reduce the amount of concrete required, or to reduce the amount of concrete that needs to be poured on-site.
One approach has been to use pre-cast concrete elements, cast at a plant, transported to the construction site after they have set, and put in place by a crane. Another approach has involved re-usable forms, for example of aluminum, that can be assembled at the construction site relatively quickly, and removed afterward for re-use.
Concrete blocks avoid the need for forms, and do not require a crane for installation, but do require a significant amount of labor to put in place.
Thus, while concrete and concrete blocks offer the benefit of being easy to obtain, and of being extremely well understood materials, they do suffer from some disadvantages. In addition, both poured concrete and concrete blocks are poor thermal insulators. This means that the space enclosed by a poured concrete or concrete block construction must be provided with insulation, unless the local climate makes it acceptable for that space to remain at or near the ambient outside temperature at all times. This consideration has led to the development of insulating concrete forms (ICFs), which are installed at the construction site, and once the concrete has been poured and set, are left in place as permanent building insulation. (ICFs are also used for floors and roofs.) These forms may be designed to interlock, to avoid the need for additional materials or tools to secure them together. Materials of which ICFs are made include polystyrene foam, polyurethane foam, cement-bonded wood fiber and cement-bonded polystyrene beads. The ICFs may serve a number of functions, including thermal and acoustic insulation, to provide space for electrical conduits and plumbing, and to provide backing for gypsum boards inside, or brick or the like outside.
Work has also been done to provide composite construction materials and elements. One example is shown in U.S. Pat. No. 7,926,233. A construction material of this kind may provide numerous benefits, including adequate strength, good thermal insulation characteristics, resistance to moisture and wetness, low susceptibility to leaks, and no susceptibility to corrosion. They may be provided in the form of modular elements, which promotes ease of assembly at the building site.
Nonetheless, some of the materials that may be used in making such construction elements are relatively expensive. For example, the materials may include plastic foam, resin, fiberglass-reinforced plastic, filler, and catalyst to promote the chemical reactions that are required to produce the finished construction element. And while one attraction of using composites is the ability to produce the construction elements in numerous shapes, it is also the case that a complex shape tends to require a complex, and hence expensive, mold. For these reasons the present inventors have considered ways to manufacture composite panels such that the product has the characteristics that make such panels attractive for use in construction, in a simpler fashion, and at a lower cost, than is conventionally possible.
As an example, a panel for use in a foundation or above-grade wall may advantageously be made with studs for adequate strength, and for use in attaching an interior wall if desired. In the mentioned patent a method is provided for producing such a panel, having integral studs, of composite materials. While the panel itself (that is, the element minus the studs) has a simple shape, the complete product does not. If the studs are formed extending outward from the panel, the overall shape is now quite complex from the viewpoint of making a mold with the proper shape in which the product can be made.